16" would be fine thats why i said 1' RANGE im not stuck to 1 foot on the mark just want something a little larger so it can go straight into my pond, but not too large that it would dwarf pondmates and my cats should be about the right size then for a 16" bowfin tankmate, just gonna have to watch aggro between it and my silver aro. it is about 14" now so it would be about the same size as the bowfin i was hoping to have it be a little bigger than the bowfin to make sure it could hold its own with it. if i need to move the aro i will be able to so 16-18" is fine.